1. Field of the Invention
The present invention is related to a valve and particularly to an electric driving device for a valve.
2. Brief Description of the Related Art
Usually, the conventional valve is opened or shut with manual operation but manual operation needs great effort and takes time. In order to overcome the deficiency, the electric motor has been applied to drive a gear train for opening and shutting the valve. However, it still needs to operate with hand in case of power failure. In addition, the prior structure allows the motor shaft rotates while the user operates the hand wheel to open or shut the valve such that a much great effort has to be exerted. Moreover, it is frequent that a lot of valves have to be operated in a working field and the operator becomes exhausted after all the valves have been opened or shut.